ARM: msm: Move core.h contents into common.h

No real need to have a separate core.h from the common.h file.  Fold
these two prototypes into the common header file.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Olof Johansson <olof@lixom.net>